In the production of castings it is inevitable, due to irregularities in the assembled mold sections and irregularities in cores and core-supporting holes formed in the mold sections, that small, undesired gaps are formed within the mold. During the subsequent casting of molten material into the mold, these gaps are penetrated by the molten material and give rise to the formation of burrs on the casting at the part line of the mold sections and where cores are supported in the mold section. These burrs have to be removed in a subsequent fettling operation.
The cost of fettling castings constitutes a considerable part of the manufacturing costs incurred in a casting shop. For steel castings, the fettling costs may amount to as much as 50% of the processing costs. The removal of the casting gate and the feeder from a casting constitute laborious and the most expensive parts of the fettling work, but the removal of burrs formed at the mold parting line and around the location of cores also involves a considerable amount of costly work. The fettling work is dirty, monotonous, heavy and unpleasant from the point of view of health and the environment. It is, therefore, desirable to mechanize the fettling work to the greatest possible extent.
It has been known in the past to employ robots in foundries for certain work operations. Thus, programmable robots have been used for handling castings or tools during the cutting of casting gates and feeders and for burr removal.
The primary object of the present invention is to provide a method of producing a casting which facilitates mechanized removal of undesired burrs from the casting.